摘 要

染料造成的水污染是现在人类发展过程中必须直面和解决的重要课题之一，然而当前绝大部分的解决方法仍存在不可回避的限制。壳聚糖（Chitosan，CS）是种天然大分子，其中氨基在酸性液体环境中质子化，所以能以静电相互作用，去除水体中部分污染物，常用作吸附剂。由于在实际使用中，CS作为染料吸附剂并不尽如人意，经过研究发现，将其经过改性后，它的分子结构发生变化，性质也发生变化甚至迥然相异，因此，壳聚糖改性成了克服其不足之处的必经之路。

本文采用乙酸为溶剂，借助PEI中氨基含量多的优点，以Chitosan分子结构中-NH₂和-OH的高反应活性为基础，以环氧氯丙烷（ECH）作为交联剂，将PEI接枝到壳聚糖结构中，制取PEI-g-Chitosan吸附剂。以刚果红仿真偶氮类染料，将PEI-g- Chitosan运用于刚果红的吸附过程，确定它的吸附性能，讨论PEI-g- Chitosan对刚果红的吸附机理。

经过实验及数据处理，本文取得如下结论：

（1）Chitosan/PEI质量比为1：4，在70°C左右反应6h时，得到的反应产物在后续的除杂和制取PEI-g-Chitosan微球工序中表现最为优秀。

（2）随着溶液中刚果红的初始浓度的变化，吸附容量会随着其变大缓步变大，吸附率会变小；吸附剂投放的质量变大，PEI-g-Chitosan吸附能力变优秀，单位吸附量会随着投放质量的增大变小； pH=4时PEI-g-Chitosan对溶液中的刚果红吸附性能最好。

（3）PEI-g-Chitosan符合Langmuir吸附等温线模型，溶液中刚果红为25 mg/L时，PEI-g-Chitosan吸附量的终值为8.94mg/L；吸附量并不随时间呈某种线性关系可以得出整个过程中不只有化学吸附，还存在着物理吸附。

关键词：聚乙烯亚胺 壳聚糖微球 刚果红 接枝改性 吸附

Preparation of Polyethylenimine Grafted Chitosan Microspheres and Adsorption Performance on Congo Red

Abstract

The water pollution caused by dyes is one of the important issues that must be faced and solved in the course of human development. However, most of the current solutions still have unavoidable restrictions. Chitosan (CHITOSAN) is a renewable natural biological macromolecule. Amino groups in the molecule are protonated in a low pH solution and have a positive charge. Therefore, some of the pollutants in the wastewater can be removed by electrostatic interaction. Used as adsorbent. Because CHITOSAN is not satisfactory as a dye adsorbent in actual use, it has been found through research that after modification of CHITOSAN, the molecular structure of CHITOSAN changes, and its properties change even as a result. Therefore, Chitosan has changed. Sex has become the only way to overcome its deficiencies.

In this paper, acetic acid was used as a solvent, and PEI was grafted into Chitosan structure by using epichlorohydrin based on the strong amino group and hydroxyl group of the Chitosan molecular structure. Imine grafted Chitosan adsorbent. Using Congo red to simulate common dyes, the polyethyleneimine-grafted Chitosan was applied to Congo red adsorption process to determine its adsorption capacity, and the adsorption mechanism of Congo red on polyethyleneimine-grafted Chitosan adsorbents was studied.

After experiments and data processing, this paper has obtained the following conclusions:

(1) When the mass ratio of CHITOSAN and PEI is 1:4, and the reaction is performed at about 70°C for 6 hours, the reaction product obtained has the best performance in the subsequent impurity removal and preparation of PEI-g-CHITOSAN process.

(2) The higher the initial concentration of Congo red solution, as the adsorption capacity get greater, the adsorption rate get lower; the higher the concentration of adsorbent, the better the adsorption performance of PEI-g-CHITOSAN, but the smaller the unit adsorption capacity; When the pH value is around 4, PEI-g-CHITOSAN has the highest adsorption capacity for Congo red solution.

(3) The PEI-g-CHITOSAN conforms to the Langmuir adsorption isotherm model. When the concentration of Congo red solution is 25 mg/L, the maximum adsorption capacity of PEI-g-CHITOSAN is 8.94 mg/L; the adsorption amount does not change over time. The linear relationship can be drawn not only for chemical adsorption but also physical adsorption.

  Keywords: polyethylenimine Chitosan microspheres Congo red graft modification adsorption

目录

摘 要 I

第一章 前言 1

1.1 染料废水问题现状 1

1.2 聚乙烯亚胺 1

1.3 壳聚糖 2

1.3.1 壳聚糖的结构 2

1.3.2 壳聚糖的改性 2

1.3.3 壳聚糖的应用和发展 5

1.3.4 壳聚糖的局限 6

1.4 吸附法处理染料废水现状 6

1.5本文思路 7

第二章 聚乙烯亚胺PEI接枝壳聚糖的制备 9

2.1 前言 9

2.2 实验药品与仪器 9

2.2.1 药品 9

2.2.2 仪器 9

2.3 实验过程 10

2.3.1 PEI-g-CHITOSAN的合成及PEI-g-CHITOSAN微球的制备 10

2.4 结果与讨论 11

2.4.1 PEI-g-CHITOSAN的制备条件的优化 11

第三章 PEI-g-CHITOSAN对刚果红吸附性能的研究 13

3.1 前言 13

3.2 实验试剂与仪器 13

3.2.1 试剂 13

3.2.2 仪器 13

3.3 实验过程 14

3.3.1 刚果红的标准曲线 14

3.3.2 单位吸附量及吸附率 14

3.3.3 吸附热力学研究 14

3.2.4　吸附动力学研究 15

3.4 结果与讨论 16

3.4.1 刚果红标准曲线的绘制 16

3.4.2 刚果红初始浓度对吸附性能的影响 17

3.4.3 PEI-g-CHITOSAN投加量对吸附性能的影响 18

3.4.4 pH值对吸附性能的影响 19

3.4.5 吸附等温线模型分析 20

3.3.6 吸附动力学分析 21

3.5 本章小结 24

第四章 结论与展望 25

4.1 结论 25

4.2 创新之处 25

4.3 展望 26

参考文献 27

致谢 30

第一章 前言

1.1 染料废水问题现状

染料大量用于多个工业领域。目前，世界上每年染料的产量约为80万吨至90万吨，其中我国每年染料的产量就约为15万吨。其中大约十分之一乃至五分之一的染料在生产与使用途中进入环境中，这之中某些染料可诱发癌症、导致畸变，对人们的健康产生威胁。所以，染料废水的处理及二次回收利用己成为人类必须面对与解决的问题。染料废水组分多样、色度深、降解难度大。偶氮染料是目前各种染料中使用最多的，占到了一半以上。其大量使用后逸散到自然环境内的部分大大不利于人类生命健康。刚果红是其中具有代表性的染料，它容易在生产使用过程中，进入水体，对生态造成破坏 。现下人们解决染料废水一般的手段有吸附法、氧化法、混凝法、薄膜分离法等。吸附法是一种行之有效的处理方法，因其操作和制取简易，性价比较好聚焦了大量关注。然而现下广泛应用的一般的吸附材料有着容量较低、速度慢、饱和之后无法循环利用等缺陷。

1.2 聚乙烯亚胺

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